As amateur radio operators, we use “73” at the end of almost every QSO… ever wonder where that ever came from? Not sure I have figured out the answer to that one yet but I do have some nifty information about the number itself! Ha! Oh… and I’ve also included an excerpt from the TV show Big Bang Theory including an explanation from Sheldon of why 73 is the best number!
Other interesting facts of the number 73…
73 is an emirp, meaning that the reverse of 73, that is, 37, is also a prime number. 73 is also the 21st prime number while 37 is the 12th prime number.
The number 21 includes factors 7 and 3. The number 21 in binary is 10101; 7 in binary is 111, 3 in binary is 11, and seventy-three in binary is 1001001. All of these are palindromes. In addition, of the 7 binary digits representing 73, there are 3 ones. Also, 37 + 12 = 49 (seven squared) and 73 + 21 = 94 = 47 × 2, 47 + 2 also being equal to seven squared. Additionally, both 73 and its mirror, 37, are sexy primes twice over, as 31, 43, 67 and 79 are all prime numbers.
The number of seconds it took for the Space Shuttle Challenger OV-099 shuttle to explode after launch.
73 is the length of the Arecibo message, sent to space in search for extraterrestrial intelligence.
In Morse code, 73 is an easily recognized palindrome ( – – · · · · · · – – ).
The rhythmic clapping at sporting events that precedes “Let’s Go!” is Morse code for “73”, an abbreviation meaning “best regards.”
Hmmmmmmm….
Till next time… 73’s!